Zileuton inhibits arachidonate-5-lipoxygenase to exert antitumor effects in preclinical cervical cancer models

Multimodal evaluation of lipoxygenase-targeting NSAIDs using integrated in vitro, SAR, in silico, cytotoxicity towards MCF-7 cell line, DNA docking and MD simulation approaches

Lipoxygenase (LOX) and cyclooxygenase (COX) pathways generate biologically active mediators implicated in inflammatory disorders and several classes of cancer. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the COX pathway by inhibiting the COX-1 and COX-2 enzymes. We reported earlier that several NSAIDs, including naproxen, aspirin and acetaminophen, inhibited lipoxygenase (LOX) enzyme at sub-micromolar concentrations. In continuation, the present work demonstrates the anti-LOX activity of nine more NSAIDs supported by in vitro, in silico, MD simulation and breast cancer cell line studies. All tested drugs displayed potent to excellent inhibitory profiles with IC50 values <24.93 ± 0.64 μM. Aceclofenac (IC50 0.85 ± 0.06 μM) was the most active drug, followed by indomethacin (IC50 1.13 ± 0.07 μM), meloxicam (IC50 1.94 ± 0.07 μM) and ketorolac (IC50 9.26 ± 0.82 μM). Celecoxib (IC50 15.81 ± 0.71 μM), lornoxicam (IC50 16.54 ± 0.28 μM) and nimesulide (IC50 19.87 ± 0.85 μM) showed excellent inhibitory profiles. Flurbiprofen (IC50 21.73 ± 0.93 μM) and etoricoxib (IC50 24.93 ± 0.64 μM) moderately inhibited the target enzyme. SAR studies revealed that active molecules decorated with the carboxylate group afforded strong binding interactions as observed by in vitro assays and structural features. Other drugs, including enol derivatives and celecoxib, also showcased enhanced binding interactions. However, the cytotoxic effects of NSAIDs against the MCF-7 breast cancer cell line did not disclose significant anticancer activity. Molecular docking studies against human 5-LOX offered the best binding affinities for aceclofenac (-13.54 kcal/mol), accompanied by conventional hydrogen bonding and hydrophobic interactions as supported by the in vitro results. Docking studies with DNA dodecamer established minor groove binding with their possible role in DNA replication and gene expression. Density functional theory (DFT) and ESP studies, MD simulations and MMPBSA free energy calculations further reiterated the stability of ligand-receptor complexes. Overall, these findings highlight the potential of targeted NSAIDs as dual COX/LOX inhibitors with broader therapeutic relevance in inflammatory disorders.

Significance of non-steroidal anti-inflammatory drugs in the prevention and treatment of cervical cancer

Cervical cancer, ranking as the fourth most common cancer in women globally, is closely linked to chronic inflammation resulting from persistent human papillomavirus (HPV) infection. Chronic inflammation mediated by cyclooxygenase (COX) has been identified as a factor in cancer onset and progression, with HPV oncoproteins E6 and E7 inducing COX activation. Nonsteroidal anti-inflammatory drugs (NSAIDs) have demonstrated the capability to significantly inhibit COX activity, playing a crucial preventive and therapeutic role in various tumors. This paper explores the therapeutic value and potential clinical applications of NSAIDs in cervical cancer by examining the mechanistic interactions between HPV and COX and the carcinogenic effects of COX in cervical cancer.

Investigation of Antimicrobial and Anti-Inflammatory Efficacy of Newly Synthesized Pyrogallol-Coumarin Hybrids: In Vitro and In Silico Studies

Background: The aim of this study is to present the synthesis of two new compounds with promising antimicrobial and anti-inflammatory properties using precursors that contain pyrogallol and coumarin units. Methods: The characterization of the obtained compounds (PCHs) (E)-N'-(1-(2,4-dioxochroman-3-ylidene)ethyl)-2,3,4-trihydroxybenzohydrazide (PCH-1) and (E)-N'-(1-(2,4-dioxochroman-3-ylidene)ethyl)-3,4,5-trihydroxybenzohydrazide (PCH-2) was performed using various spectroscopic methods in combination with the DFT methods. To evaluate antimicrobial and anti-inflammatory activities, PCHs were tested against 13 different types of microorganisms and soybean lipoxygenase. To determine the specific mechanisms of anti-LOX activity, molecular docking and molecular dynamics studies were performed. Results: These compounds had the most potent antibacterial activity against the bacterium Proteus mirabilis ATCC 12453, with a MIC value of 31.125 µg/mL. In addition, three standard bacterial species were chosen to evaluate the antibiofilm activity of tested substances. The results showed that the strongest effect of PCH-2 was noticed on the biofilm formation of Staphylococcus aureus ATCC 25923 (BIC50 at 378 µg/mL). The anti-LOX results indicate that PCHs have excellent activity with the IC50 value for PCH-1 = 38.12 μM and PCH-2 = 34.12 μM. Conclusions: The obtained in vitro and in silico results confirm the strong inhibitory potential of the investigated compounds.

Qijiao Shengbai Capsule alleviated leukopenia by interfering leukotriene pathway: Integrated network study of multi-omics

BACKGROUND

Leukopenia could be induced by chemotherapy, which leads to bone marrow suppression and even affects the therapeutic progression of cancer. Qijiao Shengbai Capsule (QSC) has been used for the treatment of leukopenia in clinic, but its bioactive components and mechanisms have not yet been elucidated clearly.

PURPOSE

This study aimed to elucidate the molecular mechanisms of QSC in treating leukopenia.

STUDY DESIGN

Serum pharmacochemistry, multi-omics, network pharmacology, and validation experiment were combined to study the effect of QSC in murine leukopenia model.

METHODS

First, UPLC-QTOF-MS was used to clarify the absorbed components of QSC. Then, cyclophosphamide (CTX) was used to induce mice model with leukopenia, and the therapeutic efficacy of QSC was assessed by an integrative approach of multi-omics and network pharmacology strategy. Finally, molecular mechanisms and potential therapeutic targets were identified by validated experiments.

RESULTS

121 compounds absorbed in vivo were identified. QSC significantly increase the count of white blood cells (WBCs) in peripheral blood of leukopenia mice with 15 days treatment. Multi-omics and network pharmacology revealed that leukotriene pathway and MAPK signaling pathway played crucial roles during the treatment of leukopenia with QSC. Six targets (ALOX5, LTB4R, CYSLTR1, FOS, JUN, IL-1β) and 13 prototype compounds were supposed to be the key targets and potential active components, respectively. The validation experiment further confirmed that QSC could effectively inhibit the inflammatory response induced by leukopenia. The inhibitors of ALOX5 activity can significantly increase the number of WBCs in leukopenia mice. Molecular docking of ALOX5 suggested that calycosin, daidzein, and medicarpin were the potentially active compounds of QSC.

CONCLUSION

Leukotriene pathway was found for the first time to be a key role in the development of leukopenia, and ALOX5 was conformed as the potential target. QSC may inhibit the inflammatory response and interfere the leukotriene pathway, it is able to improve hematopoiesis and achieve therapeutic effects in the mice with leukopenia.

The role of human 5-Lipoxygenase (5-LO) in carcinogenesis - a question of canonical and non-canonical functions

5-Lipoxygenase (5-LO), a fatty acid oxygenase, is the central enzyme in leukotriene (LT) biosynthesis, potent arachidonic acid-derived lipid mediators released by innate immune cells, that control inflammatory and allergic responses. In addition, through interaction with 12- and 15-lipoxgenases, the enzyme is involved in the formation of omega-3 fatty acid-based oxylipins, which are thought to be involved in the resolution of inflammation. The expression of 5-LO is frequently deregulated in solid and liquid tumors, and there is strong evidence that the enzyme plays an important role in carcinogenesis. However, global inhibition of LT formation and signaling has not yet shown the desired success in clinical trials. Curiously, the release of 5-LO-derived lipid mediators from tumor cells is often low, and the exact mechanism by which 5-LO influences tumor cell function is poorly understood. Recent data now show that in addition to releasing oxylipins, 5-LO can also influence gene expression in a lipid mediator-independent manner. These non-canonical functions, including modulation of miRNA processing and transcription factor shuttling, most likely influence cancer cell function and the tumor microenvironment and might explain the low clinical efficacy of pharmacological strategies that previously only targeted oxylipin formation and signaling by 5-LO. This review summarizes the canonical and non-canonical functions of 5-LO with a particular focus on tumorigenesis, highlights unresolved issues, and suggests future research directions.

ALOX5 acts as a key role in regulating the immune microenvironment in intrahepatic cholangiocarcinoma, recruiting tumor-associated macrophages through PI3K pathway

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is poorly treated due to the presence of an inhibitory immune microenvironment. Tumor-associated macrophages (TAM) are an important component of TME. ALOX5 is an important lipid metabolism enzyme in cancer progression, but the mechanism by which it regulates TAM to promote ICC progression is unknown. The aim of this study was to investigate the potential mechanism of TAM regulation by ALOX5 and the translational effect of targeting ALOX5.

METHODS

In this study, we investigated the association between the spatial localization of epithelial cells and TAMs by combining scRNA-seq analysis with multiplex immunofluorescence analysis. Through bulk sequencing analysis and spatial analysis, lipid metabolism genes closely related to TAM infiltration were screened. In vitro co-culture model was constructed to verify that ALOX5 and its downstream metabolite LTB4 promote M2 macrophage migration. Bulk sequencing after co-culture combined with single-cell analysis was performed to identify key pathways for up-regulation of M2 macrophage migration. Finally, the effect of CSF1R inhibitor (PLX3397) combined with ALOX5 inhibitor (Zileuton) in vivo was investigated by by xenograft tumor formation experiment in nude mice.

RESULTS

ALOX5 in ICC cells was a key lipid metabolism gene affecting the infiltration of M2 macrophages in TME. Mechanically, LTB4, a metabolite downstream of ALOX5, recruited M2 macrophages to migrate around tumor cells by binding to BLT1/BLT2 and activating the PI3K pathway, which ultimately lead to the promotion of ICC progression. Targeting CSF1R in combination with ALOX5 inhibitor effectively reduced tumor volume and M2 macrophage infiltration abundance.

CONCLUSION

In ICC, LTB4, a metabolite secreted by ALOX5 of epithelial cells, binded to BLT1/BLT2 on TAM surface to activate PI3K pathway and promote TAM migration, thus promoting ICC progression. Targeting CSF1R in combination with ALOX5 inhibitor for ICC is a promising combination therapy modality.

5-lipoxygenase as a target to sensitize glioblastoma to temozolomide treatment via β-catenin-dependent pathway

Sensitizing strategy is required to improve the clinical management of glioblastoma (GBM). 5-Lipoxygenase (Alox5) has been recently garnered attention due to its pro-carcinogenic roles in various cancers. This study demonstrates that Alox5 is overexpressed in GBM but not normal neuronal tissues. Alox5 depletion inhibits the growth of GBM cells, both in bulky and stem-like populations, and enhances the anti-cancer effects of temozolomide. The mechanism behind this involves a decrease in β-catenin level and activity upon Alox5 depletion. The inhibitory effects of Alox5 can be reversed by the addition of a Wnt agonist. Additionally, the study reveals that zileuton, an Alox5 inhibitor approved for asthma treatment, significantly improves the efficacy of temozolomide in mice without causing toxicity. Combination index analysis clearly demonstrates that zileuton and temozolomide act synergistically. These findings highlight the importance of Alox5 as a critical regulator of glioblastoma sensitivity and suggest the potential repurposing of zileuton for GBM treatment.

The ALOX5 inhibitor Zileuton regulates tumor-associated macrophage M2 polarization by JAK/STAT and inhibits pancreatic cancer invasion and metastasis

5-lipoxygenase (encoded by ALOX5) plays an important role in immune regulation. Zileuton is currently the only approved ALOX5 inhibitor. However, the mechanisms of ALOX5 and Zileuton in progression of pancreatic cancer remain unclear. Therefore, we investigated the effects of Zileuton on tumor-associated macrophage M2 polarization and pancreatic cancer invasion and metastasis, both in vivo and in vitro. In bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) analyses, we found a significant association between elevated levels of ALOX5 and poor survival, adverse stages, M2 macrophage infiltration, and the activation of JAK/STAT pathways in macrophages. In clinical samples, immunofluorescence, quantitative real-time PCR and immunohistochemical results verified the high expression of ALOX5 in pancreatic cancer, primarily in macrophages. We constructed PANC-1 human pancreatic cancer cells and macrophages overexpressing ALOX5 using lentivirus. In PANC-1 pancreatic cancer cells, low-dose Zileuton inhibited PANC-1 cell invasion and migration by blocking ALOX5. In macrophages, ALOX5 induced the M2-like phenotype through the JAK/STAT pathway and promoted the chemotaxis of macrophages towards PANC-1 cells, while Zileuton can inhibit these effects. We constructed the nude mouse model of in situ transplantation tumor of pancreatic cancer. After treatment with Zileuton, the mice showed increased survival rates and reduced liver metastasis. These findings indicate that ALOX5 regulates tumor-associated macrophage M2 polarization via the JAK/STAT pathway and promotes invasion and metastasis in pancreatic cancer. Zileuton can inhibit these effects by inhibiting ALOX5. These results provide a theoretical basis for the potential use of Zileuton in the treatment of pancreatic cancer.

Three-dimensional growth reveals fine-tuning of 5-lipoxygenase by proliferative pathways in cancer

The leukotriene (LT) pathway is positively correlated with the progression of solid malignancies, but the factors that control the expression of 5-lipoxygenase (5-LO), the central enzyme in LT biosynthesis, in tumors are poorly understood. Here, we report that 5-LO along with other members of the LT pathway is up-regulated in multicellular colon tumor spheroids. This up-regulation was inversely correlated with cell proliferation and activation of PI3K/mTORC-2- and MEK-1/ERK-dependent pathways. Furthermore, we found that E2F1 and its target gene MYBL2 were involved in the repression of 5-LO during cell proliferation. Importantly, we found that this PI3K/mTORC-2- and MEK-1/ERK-dependent suppression of 5-LO is also existent in tumor cells from other origins, suggesting that this mechanism is widely applicable to other tumor entities. Our data show that tumor cells fine-tune 5-LO and LT biosynthesis in response to environmental changes repressing the enzyme during proliferation while making use of the enzyme under cell stress conditions, implying that tumor-derived 5-LO plays a role in the manipulation of the tumor stroma to quickly restore cell proliferation.

Knock-out of 5-lipoxygenase in overexpressing tumor cells-consequences on gene expression and cellular function

5-Lipoxygenase (5-LO), the central enzyme in the biosynthesis of leukotrienes, is frequently expressed in human solid malignancies even though the enzyme is not present in the corresponding healthy tissues. There is little knowledge on the consequences of this expression for the tumor cells regarding gene expression and cellular function. We established a knockout (KO) of 5-LO in different cancer cell lines (HCT-116, HT-29, U-2 OS) and studied the consequences on global gene expression using next generation sequencing. Furthermore, cell viability, proliferation, migration and multicellular tumor spheroid (MCTS) formation were studied in these cells. Our results show that 5-LO influences the gene expression and cancer cell function in a cell type-dependent manner. The enzyme affected genes involved in cell adhesion, extracellular matrix formation, G protein signaling and cytoskeleton organization. Furthermore, absence of 5-LO elevated TGFβ₂ expression in HCT-116 cells while MCP-1, fractalkine and platelet-derived growth factor expression was attenuated in U-2 OS cells suggesting that tumor cell-derived 5-LO shapes the tumor microenvironment. In line with the gene expression data, KO of 5-LO had an impact on cell proliferation, motility and MCTS formation. Interestingly, pharmacological inhibition of 5-LO only partly mimicked the KO suggesting that also noncanonical functions are involved.

Ferroptosis: a potential therapeutic target for Alzheimer's disease

The most prevalent dementia-causing neurodegenerative condition is Alzheimer's disease (AD). The aberrant buildup of amyloid β and tau hyperphosphorylation are the two most well-known theories about the mechanisms underlying AD development. However, a significant number of pharmacological clinical studies conducted around the world based on the two aforementioned theories have not shown promising outcomes, and AD is still not effectively treated. Ferroptosis, a non-apoptotic programmed cell death defined by the buildup of deadly amounts of iron-dependent lipid peroxides, has received more attention in recent years. A wealth of data is emerging to support the role of iron in the pathophysiology of AD. Cell line and animal studies applying ferroptosis modulators to the treatment of AD have shown encouraging results. Based on these studies, we describe in this review the underlying mechanisms of ferroptosis; the role that ferroptosis plays in AD pathology; and summarise some of the research advances in the treatment of AD with ferroptosis modulators. We hope to contribute to the clinical management of AD.

Liquid chromatography coupled to high-resolution mass spectrometry metabolomics: A useful tool for investigating tumor secretome based on a three-dimensional co-culture model

Three-dimensional (3D) cell culture technologies, which more closely mimic the complex microenvironment of tissue, are being increasingly evaluated as a tool for the preclinical screening of clinically promising new molecules, and studying of tissue metabolism. Studies of metabolites released into the extracellular space (secretome) allow understanding the metabolic dynamics of tissues and changes caused by therapeutic interventions. Although quite advanced in the field of proteomics, studies on the secretome of low molecular weight metabolites (< 1500 Da) are still very scarce. We present an untargeted metabolomic protocol based on the hybrid technique of liquid chromatography coupled with high-resolution mass spectrometry for the analysis of low-molecular-weight metabolites released into the culture medium by 3D cultures and co-culture (secretome model). For that we analyzed HT-29 human colon carcinoma cells and 3T3-L1 preadipocytes in 3D-monoculture and 3D-co-culture. The putative identification of the metabolites indicated a sort of metabolites, among them arachidonic acid, glyceric acid, docosapentaenoic acid and beta-Alanine which are related to cancer and obesity. This protocol represents a possibility to list metabolites released in the extracellular environment in a comprehensive and untargeted manner, opening the way for the generation of metabolic hypotheses that will certainly contribute to the understanding of tissue metabolism, tissue-tissue interactions, and metabolic responses to the most varied interventions. Moreover, it brings the potential to determine novel pathways and accurately identify biomarkers in cancer and other diseases. The metabolites indicated in our study have a close relationship with the tumor microenvironment in accordance with the literature review.